The goal of this proposed research to augment the available tracers for measurement of defects of myocardial metabolism with Positron Emission Tomography (PET). Specifically efforts will focus upon the development of 11C-labeled fatty acids whose altered metabolism in effected patients will aid in the diagnosis of medium chain acetyl coenzyme A deficiencies (MCAD). MCAD has been implicated in numerous cardiac diseases including sudden death in infants. There is currently no diagnostic approach available for this disease. MCAD patients exhibit an altered rate of metabolism in the final stages of the Beta-oxidation cycle which requires the defective enzyme(s). Carbon-11 labeling of long chain fatty acids in late-chain positions will allow measurement of this altered metabolic rate with PET. The radiochemical preparation and purification of omega[11C]palmitic acid for future evaluation in humans and the initial synthesis and preparation of 15[11C]palmitic acid will provide two potential tracers for this disease.